microscope image

Shown is an electron microscope image of liver hepatocyte cells. Colours highlight mitochondria, nuclei and membranes, automatically identified using machine learning. (Work of Ronald Xie, Gary Bader, Sonya MacParland, Ian McGilvray and Mei Zhen).

Gary Bader, Sonya MacParland, and Ian McGilvray, have collaborated on a world first: generating a “map” of all cells of the human liver.

In 2016, Gary Bader returned from a Human Cell Atlas (HCA) meeting with the goal to map a human organ cell by cell for insights into its functioning.

Bader, a University of Toronto (U of T) professor of computational biology and now part of the HCA organizing committee, credits Medicine by Design for enabling the project. With the support of Medicine by Design, Bader formed a collaboration with MacParland, a senior scientist from the Ajmera Transplant Centre, University Health Network (UHN), and an associate professor at U of T, and McGilvray, a transplant surgeon at the Ajmera Transplant Centre, and professor at U of T.

“We didn’t choose liver, I guess you could say liver chose us,” Bader says, adding that Toronto has unique expertise in single-cell genomics, an outstanding liver research community and access to liver tissue through UHN — crucial components that allowed the successful completion of the liver mapping project.

“It seems nowhere else in the world had all the pieces, and Medicine by Design put those pieces together,” he says.

The detailed mapping of cell types and their functions are shedding light on tissue aging, repair processes, and the development of stem cell therapies. The creation of maps at the single-cell level, such as the map of human liver cells, offers valuable benchmarks for researchers working on regenerative medicine projects. The mapping team published their first draft, which they continue to work on and refine, in 2018.


(Right to left:) Sonya MacParland and Ian McGilvray (University Health Network), and Gary Bader (Univeristy of Toronto). (Photo provided by UHN.)

The HCA is a massive world-wide effort and is mapping every organ. On a scale similar to the Human Genome Project, HCA involves global collaboration across various scientific disciplines, including genomics, technology development, basic biology, clinical research, computational biology, and ethics.

The team is applying their insights into liver biology to advancing the knowledge and understanding of treating liver diseases like primary sclerosing cholangitis (PSC).

Back to “Five ways Medicine by Design is transforming the treatment of liver disease.”